Dental implants are widely used as artificial substitutes for the root portion of missing teeth, and allow a tooth prosthesis to be securely anchored to the jaw, for example via a permanent abutment mounted to the implant. Endosseous implants generally comprise an externally threaded body, often self-taping into the bone tissues, and further comprise an internal chamber that is configured, typically internally threaded, for receiving and securing therein the anchoring stem of a permanent abutment therein.
Also well known in the art are dental analogs, each of which is a replica of a corresponding dental implant. A dental analog has an internal passage and an interface structure that are respectively identical to the internal passage and interface structure of the implant that is designed to receive, engage and secure the prosthesis and permanent abutment; however, in contrast to the dental implant, the dental analog is not intended for implantation in a human, but rather for use with a physical model of the intraoral cavity or part thereof.
Conventionally, following implantation of a dental implant in the intra oral cavity and healing of the surrounding tissues, a physical model of the intra oral cavity is often produced for facilitating design and manufacture of the permanent abutment and the prosthesis or other restoration that is to be eventually mounted onto the implant. In one procedure, an impression abutment is mounted to the implant so that it projects into the intra oral cavity, and an impression is then obtained of the intraoral cavity using well known techniques (for example, as are known in the art regarding fixture level impressions) and impression materials, for example PVS. The impression abutment can be of the pick-up type, to be embedded with the impression material and retained therein after the impression tray is removed. Alternatively the impression tray is removed without the impression abutment attached thereto, but nevertheless having a recess formed therein complementary to the outer shape of the impression abutment, enabling the transfer-type impression abutment to be mounted therein at a later time. Subsequently an analog, corresponding to the particular implant that is implanted in the patient, is attached to the impression abutment, which is in situ in the impression material, and plaster is poured into the impression tray including the analog to produce a positive plaster model of the intraoral cavity with the analog embedded. The analog is in a spatial disposition, i.e., at a position and orientation, in the plaster model corresponding to the spatial disposition of the implant in the patient's intra oral cavity. The dental technician can now attach a permanent abutment, or custom design a permanent abutment to fit the implant, and build a coping or bridge framework or prosthesis to fit into the intraoral cavity of the patient.
US 2010/0021859, assigned to the present Assignee, discloses a method and system for manufacturing a physical dental model. A virtual model is provided representative of at least a portion of the intra-oral cavity including at least one dental implant implanted therein, and the virtual model includes a virtual portion representative of each dental implant. A physical model is then manufactured based on the virtual model, the physical model including a physical analog corresponding to each implant at a respective physical spatial disposition with respect to the physical model corresponding to the respective virtual spatial disposition of the respective virtual portion with respect to the first virtual model.
By way of general background, the following publications relate to implants, analogs or to dental procedures relating to dental implants or analogs: U.S. Pat. No. 6,358,052, US 2010/0112527, US 2008/032262, US 2007/0092854, US 2006/183078, US 2003/0162148, WO 2010/108919, US 2011/294093.
Herein the “the coronal direction” with respect to a tooth refers to the direction originating from the region of the tooth root below the jaw towards the region of the crown above the jaw, while “the apical direction”, refers to the direction opposite to the coronal direction.